Artificial rubber



Patented Oct. 13, 19 31 UNITED STATESTIPATENT. OFFICE EDUABD rsenumnm AND WALTER 13001:, or COLOGNE-MULHEIM, GERMANY ARTIFICIAL R BBER No Drawing. Application filed August 17, 1929, Serial No. 386,780, and in Germany 1m 10,1927.

The present inventionrelates to a process of vulcanizing masses obtained by polymerization of diolefines and to, new products obtainable by such vulcanization.

: In accordance with the invention at least two different plastic or elastic masses, produced according to various polymerization processes from diolefines, such as butadiene (l.3), isoprene, 2.3-d-imethylbuta liene In (-4.3) or homologues and analogues thereof,

are intimately mixed prior to vulcanization with a finely divided soot variety whereby it is to be understood that the term finely divided is intended to include dimensions of 5 particles ranging from those of lamp black to colloidal dimensions. As soot varieties may bementioned b way of example carbon black, lamp black, oil soot and the' like.

vulcanization can be er formed according 0 to any desired method, or instance by heatucts of technically high qualities resem ling soft rubber vulcanizates. The employment of mixtures containing different pol eri- .zates makes it possible to vary the nu ity of the vulcanizate obtained considerab yin any desired direction, whereas considerably less variation is possible when employing onl' a single pol merizate. Such mixtures-of (lifferent po ymerization products are obtainable according to most various methods, for

polymerizate's b rolling or knea ing or by polymerizing mixtures of diflerent didlefines according to any desired process, or by poly merizing such a diolefine in the presence of valuable results, the vulcanizates being rod- '1 instance bym'echanically mixin .difierent" 'an incompletel or completely polymerized mass derived rom another diolefine, or bypolymerizing one'and the same diolefine gradually according to difi'erent polymerization methods.

The vulcanizatesobtained from such mixtures with the addition ofa soot variety com-- I bine good tensile strength with a good stretch, especially in cases where carbon black has been added. In the latter case, for instance,

product's possessing a tensile.

strength between about 150-275 kilograms per square centimeter at a stretch of about 400- 800% generally are obtainable, whereas in case of applying other finely divided fillers the corresponding figures will generally only amount to about -150 kilograms per square centimeter and 300-60076.

. The quality of rubber goods is often characterized by the so called index of strength,

that is to say by the product of tensile stren th inkilograms per square centimeter and t e ercentage stretch. When applying this method of characterizing the qua 'ty 0 our vulcanization products, fi res between about 50.000 and 190.000 wil generally be obtainable, whereas without the addition of a finely dlvided soot variety' only (moanizateshaving es fi uring between about I, 15000 to 40000 are obtainable, The i q eament in qualitiesv of* our"n'ew" vulcanizates compared withthatof the latter therefore amounts u to a-b'out600-900%, whereas the known ad ition of carbon black to rubber.

only produces an improvement in qualities below about 100%.

It may be mentioned that all the figures given above, es eciallythe proportion between the tensi e stren h and stretch will ya within the widest imits depending as wel on the starting pol' merization an an on the kind and uantity of the soot variety added in the fine y divided state, car

bon black generally being superior in its method of manufactureand the size and form of particles of the soot variety influence the properties of the vulcanization products toa farreaching extent. 1

action-to the other soot variety. Also the hydrocarbons as on the vulcanization methods which are'strictly within the figures mentioned above, but is intended to include all the vulcanizateswhich are obtainable by vulcanizing' mixtures containing, at least two different polymerizates' of diolefines and a finely divided soot variety.

The quantities of the soot variet to be added vary within wide limits. 11. some cases already ratherusmall amounts of the soot variety, for example carbon black will yield useful vulcanizates, but-in most cases, especially when starting with rather plastic 01 erizates amounts between about 30- 8()% (calculated upon the olymerizate ,will be useful to produce canizates 0 high technical value.

Obviously besides the soot varieties mentioned other additions promoting or influencing the vulcanization process or the quality of the vulcanizates, such as vulcanization accelerators, plastifying a cuts, as for instance resins, oils, hydrocar ons, etc. may added without departin from our invention. Also it will generall e useful toadd, besides the finely d'vided soot variety, other finely divided fillers or such, os'sessing a larger size of particles than de ed by the expremion finely dividedb I The following examples will illustrate our invention without limiting it thereto, the parts being by weight.

Ewample 1 About 75 parts of butadiene and about 75 parts of 1.3-dimethyIbutadiene are emulsied with 150 parts of water and 15 parts of sodium stearate and polymerized at about 70 C. for about one week. The olymerir zates thus obtainable are mixed wit 3 parts of sulfur, 15 parts of zinc oxide, 2 arts of tar, 2 arts of stearic acid, 50% 0 carbon black Exalculated upon the mixed polymerizate) and 1' part of diphenylguanidme by rolling and the mixture is vulcanized by heating for about 40-50 minutes to a temperature of about 135-140 C. In this manner, or according to similar vulcanization methods, vulcanizates are obtainable possessing a tensile strength of about 180-250 kil ams per square centimeter at a stretch of a ut 600- 800%. whereas the corresponding figures in the absence of carbon black will be 30-50 kilograms per square centimeter and 300- 500%.

Vulcanizates of similar properties are obtainable when replacing the -1.3-dimethylbutadiene by 2.3-dimethylbutadiene or by causing polymerization to take place in the presence of water and another suitable emulsifying agent and vulcanizing as described above, or by starting with the correspondjn isopreae-dimethylbutactiene mixture orwi butadiene isoprene-dimethylbutadiene mixa tures' of difierent composition and otherwise working in the same 'manner. 1

Ewwmple 2 A mixed polymerizate is prepared by heating 100 parts of butadiene to -75 C. for about one month adding 50 parts of butadiene, 7 .5 parts oi glue 7.5 arts of the sodium salt of isobutylnaphtha ene sulfonic acid and 150 arts of water and shaking the reaction mlxture for about two weeks at a temperature of 60-70 C.

The polymerizate thus obtainable is mixed by rolhn with 2 parts of sulfur 10 parts of zmc oxi e, 3 parts of stearic-aci 2 parts of tar, 1 part of pitch, 45 arts of carbon black and 15 parts of thiocar anilide and vulcanized at a temperature of about 135-140 G. Vulcanizates are thus obtainable possessing a tensile strength of about 150-170 kilograms per square centimeter at a stretch of about 500-600%, whereas the corresponding figures of the same vulcanizates, but without the adbe dition of carbonblack, are 30-40 kilo ams quantity of isoprene.

Ewample 8 To 100 parts of butadiene, 0,2-0,4 part of sodium wire. is added and the mixture is polymerizedfor about 3 to 4 days at normal temperature in a nitrogen atmosphere. 30

parts of the lymerizate thus obtainable are dissolved in 150 parts of butadiene (if desired with the addition of a suitable organic solvent, such as turpentine oil, ligroin and the like), and the solution is emulsified with 150 parts of water and 15- parts of sodium steal-ate and heated to about 50 C. for about one week, while continually shaking. Y

The mixed olymerizate thus obtainable is mixed by rol ing or kneading with 3 parts of sulfur, 15 partsof zinc oxide, 2 parts of stearic acid, 2 parts of tar, 55 parts of carbon black and one part of diphenylguanidine and vulcanized folinstance by heating to about.135- C. Vulcanizates are thus obtainable possessing a tensile strength of about 160-200 kilograms per square centimeter at a stretch of about GOO-800%, .whereas the corresponding figures without the ad- ,dition of carbon black are 30-50 kilograms per square centimeter and 300400%.

When replacing in-this example the butadiene by isoprene, vulcanizates of somewhat similar properties will be obtained.

I Example 4 100 parts of butadiene are emulsified with 15 parts of sodium stearate and parts of fore or after water and p "erized at about 65. 0. Beishinfg of the polymerizatlon process 100 parts 0 are added and the mixture is further polymerized at the same temperature while shaking or stirring. A plastic homogenous mass is thus obtained yielding, when vulcanized as describedin Example 3 with the addition of 60% of carbon black, resilient vulcanizates, possessing a tensile strength of 175-200 kilograms per square centimeter at a stretch of 500-800%, whereas the corresponding figures without the addition of carbon black are about 30-60 kilograms per square centimeter and about 300-500%.

Somewhat similar products are obtainable by replacing butadiene by the equivalent amount of isoprene.

. E'a-ample 5 50 parts of 2.3 dimethylbutadiene are heated to 70 C. until about half 'of the dimethylbutadiene has pblymerized. To this mixture 100 parts of butadiene,,12 parts of .sodium stearate and 100 parts of water are added, the mixture is emulsified and further polymerized at about 60-70 C. The mixed polymerizate thus obtainable is vulcanized with the addition of 50% of carbon black (calculated on the mixed vulcanizate) as described in Example 4, yielding vulcanizates possessing a tensile strength of about 180-250 kilograms per square centimeter, at a stretch of 500-7 00%, "whereas the corresponding fi'gures without the addition of carbon black will be'about 30-60 kilograms per square centimeter and 300-500 Example 6' (Lparts of butadiene and 75 methylbutadiene are heated to arts of di- Example 7' 50 parts of a product, obtained by polymerizing 2.3-dimethylbutadiei1e at about 70-7 5 (1,- and 50 parts of amass, obtained by polymerizin isoprene in emulsion with an equal part 5f water and about 10% of the sodium salt of castor oil sulfonic acid (Turkey-red oil), are mixed. by rollin' or kneading. The mixture thus obtaine is vulcanized in any desired manner after the 2.3-dimethylbutadiene' carbon black as described in with.30 parts of a mass,

0 C. for about 4-6 weeks. A homogeneous plastic addition of 50% its weight of carbon black,

a vulcanizate possessing a tensile strength of 150-175 kilograms per square centimeter at a stretch of 500-650%, being thus obtainable.

Eaample? About parts of a product, obtained by polymerizingbutadien'e in emulsion with the equal part of water, 5% of sodium stearate and 7.5% of the sodium salt of isobutylnaph- .thalene sulfonic acid and heating the emulsion to about -40 0., are introduced into a mixture of 100 parts of butadiene and 100 parts of ligroin, 0.75 parts of sodium wire is added and further polymerization is performed by heating to a temperature of about 15-35 C. When vulcanizingv this polymerizate with the addition of its weight of Example 4, elastic vulcanizates are obtained, possessing a tensile strength of 150-200 kilograms per square centimeter at a stretch of GOO-800%.

Example 9 parts of butadiene are emulsified with 100 parts of 10% aqueous sodium oleate solution, 3 parts of ma esium oleate and 5 parts of 1/1- 11 caustic so a solution, theemulsion is made homogeneous and caused to polymerize by heating to about 60 C. for about 2 days. The mass thus obtainable is mixed by rolling obtained by shaking butadiene in the presence of 0.2% its weight of sodium wire at room temperature for about 3 days. To 100 parts of this mixed polymerizate 60 parts of carbon black, 15 parts of zinc oxide, 2 parts of stearic acid,-

2 parts of colophony, 1 part of sulfur and 1,3 parts of the dithiocarbamate of tetrahydroquinaldine are added and vulcanization is effected byheating to'about 135-140 C. A vulcanizate is thus obtainable possessing a tensile strength of about 170-200 kilograms per square centimeter at a stretch of-about GOO-700%..

This is a continuation in part of our copfnding application Serial .No. 281,587filed ay 29,1928. A

We claim 1. As new products the vulcanizates obtainable by vulcanizing amixture two different solid polymerization products of diolefines, inQthe presence of about 3080% its weight of a soot variety in-a finely divided form, said vulcanizates generally possessing indices of strength between about 50.000 and of at least able by vulcanizing a of at least two difierent solid polymerization products of a hydrocarbon of the dgroup consistmg of butadiene, isoprene an dimethylbutadienes, in the presence of a soot variety in a finely divided form, said vulcanizates generally possessing indices of strength between about 50.000 and 190.000.

4. As new products the vulcanizates obtainable by vulcanizing a mixture of at least two different solid polymerization products of a hydrocarbon of the group consistin of buta- I diene, isoprene and dimethylbuta ienes, in the presence of carbon black, said vulcanizates generally possessing indices of strength between about 504000 and 190.000.

5. As new products the ,vulcanizates obtainable by vulcanizin a mixture of at least. two difierent solid 0 ymerization products of a hydrocarbon o the oup consisting of butadiene, isoprene and unethylbutadienes,

i in the presence of about -80% its weight of a soot variety'in a finely divided form, said vulcanizates generally possessing indices of strength between aboutf50.000 and 190.000.

6. As new roducts the vulcanizates obtainable by vu oanizin amixture of at least two different solid 0 ymerization products of a hydrocarbon o the roup consisting of -tainableby pol merizing about equal parts butadiene, isoprene and imethylbutadienes, in the presence of about 30-80% its weight of carbon black, said vulcanizates generally possessin indices of strength between about 50.000911 190.000. a

7. As new products the vulcanizates obofbutadiene an a compound of the formula:

cnFo -odan Y I I Ha g i v wherein one at narans hydrogen and the other :1: stands for methyl, in the presence of water and of an emulsifying agentyand vulcanizing the mixed polymerizates thus obtainable wit the addition of about 50% their weight of carbon black, said rubber oods possessing a tensile strength betweena out -250 kilograms per square centimeter at a stretch of about 600+800%.

Intestimony whereof we'have hereunto set our hands.

. EDUARD TSCHUNKUR. [1 5.]

WALTER BOCK. [n a] 

